I am working with a unit which claims to be NMEA compliant but does not seem to switch ID when a conflict arise. I am having issue with the address claiming process. I order to determine who has priority I have to compare "Names". I read "A Comprehensive Guide to J1939" as well as the PGN 60928 definition from NMEA and I am having problem properly identifying each field from the Byte Stream.
For the Murphy the stream is: 7A 6B C3 09 10 A0 A0 C0
For the other unit the stream is: 28 87 41 26 00 01 C8 C0
If I decode the field in bit stream I obtain the following. First colum refer to NMEA Field Data Definition number.
Field___ |____________Murphy__________ ||___________Sleipner____________
------------------------------------------------------------------------------------------------
1-DD173 | 000110110101101111010| 224122|| 000011000011100101000| 100136
2-DD172 | __________00001001110| ____78|| __________00100110010| ___306
3-DD201 | __________________000| _____0|| __________________000| _____0
4-DD174 | ________________00010| _____2|| ________________00000| _____0
5-DD171 | _____________10100000| ___160|| _____________00000001| _____1
6-DD175 | ____________________1| _____1|| ____________________1| _____1
7-DD170 | ______________0100000| ____32|| ______________1001000| ____72
8-DD169 | _________________0000| _____0|| _________________0000| _____0
9-DD168 | __________________100| _____4|| __________________100| _____4
10-DD001| ____________________1| _____1|| ____________________1| _____1

Problem is I get some inconsistencies between Field 6-DD175(reserved bit) and 10-DD01 Arbitrary Address Capable.
According to Wilfried Voss,
Field 6 is Bit 1 of Byte 7
Field 10 is Bit 8 of Byte 8
Question is what is bit 1 and what is bit 8? Working from the kown Manufacturer Code of both units I came to the conclusion that Bit 1 is in fact the Most significant bit of the Byte. But if I am consistant with this definition then Field 6 is set to 1 which is contrary to both J1939 and NMEA definition. Now if the convention is Bit 1 is the least significant then Field 10 becomes 0 which would indicate that neither unit are Arbitrary address capable. This would not be compliant to NMEA as I understand it nor is it consistent with the encoding of the manufacturer's names.
I would appreciate some insights from the expert on the matter. I have attached a Spreadsheet I used to decode those names if you are interested.

Arbitrary Address Capable is the 8th bit of the 8th byte.

I've looked in our code and we are setting the reserved bit to 0, so this would be a bug, and we will need to fix this in the future.

We have run the NMEA compliance tests and will bump the address appropriately. The other piece of equipment may not be doing this correctly.

Thanks for your answer. Funny part is that 2 out of two comapnies I work with seem to have the same bug. Both ran through the NMEA compliance tool and did not report the issue.
As far address switching, Yes the other unit should have changed its address because the Name is larger. We are working on the issue.
JM